In 'The Last Battle,' the Unicorn says that humans are brought to Narnia when Narnia is troubled. And Narnia is in trouble now: A false Aslan roams the land. Narnia's only hope is that Jill and Eustace, old friends of Narnia, will be able to find the true Aslan and restore peace to the land. Softcover. 211 pages. for ages 8 and up. There are seven books in all: The Magician's Nephew; The Lion, The Witch And The Wardrobe, The Horse And His Boy, Prince Caspian, The Voyage Of The Dawn Treader, The Silver Chair, and The Last Battle.